As officers moved into a crowd about 100 strong, protesters began chanting, "We are the 99 percent. We are the 99 percent."

Moments after an announcement that the park had closed at 10 p.m., 12 police officers on bicycles rode through the park, then surrounded a sole tent in the north end occupied by two men.

As officers looked inside the tent, the crowd chanted, "The whole world is watching. The whole world is watching."

The first man was arrested and taken to a paddy wagon.

As a second person in the tent was arrested, the crowd applauded.

Soon, protesters were chanting, "Hey, hey. Ho, ho, Mike McGinn has got to go," referring to Seattle Mayor Mike McGinn. More than 70 protesters blocked the entrance to the park.

Arrests were expected. Wednesday morning, McGinn issued a news release saying he'd instructed the Parks Department and the police to enforce the rules at Westlake Park. Those rules prohibit tents and camping and remaining in the park after 10 p.m.

Then, just before 11 p.m., all the police left. They had not returned by midnight.

A group of about 20 sat huddled together, expecting possible arrest. "Tell the world we are peaceful," one woman said.

The arrests did not surprise Maria Guillen, one of the facilitators at Westlake Park Wednesday night. "They've been trying to divide us for so long," she said, accusing the mayor and the city of inconsistent policies toward the protesters.

As drums beat in the background, she added, "We're alive, happy and energetic."

Another two protesters were arrested Wednesday afternoon at City Hall. Seattle police said they failed to leave the building at the 6 p.m. closing time and were booked into King County Jail for investigation of criminal trespassing.

In the same meeting, protesters urged a massive turnout at the park on Saturday. Fliers were distributed asking people to join "the night of 500 tents."

Many on Wednesday night said they were ready to take a stand and be arrested.

They urged those who did not want to be arrested to step off park property and onto the sidewalk to witness any police action, in case arrests were made.

A day earlier, many people favored the idea of camping outside City Hall, which McGinn had offered. But a core of protesters said they were committed to staying at Westlake and asked the others to support them for "solidarity."

Early Thursday morning, only one tent had been pitched outside City Hall.

College students lend support

Wednesday afternoon, protesters were boosted by the influx of hundreds of college students from local campuses. A crowd of about 500 gathered at Westlake, cheering speaker after speaker who called the "Occupy" movement the most important, grass-roots social movement in a generation.

About 200 members of the group had walked from the University of Washington. Smaller contingents also came from Seattle Central Community College, Bellevue College and other schools.

Guillen, 24, a recent UW grad, led loud chants of "money for jobs and education, not for war and occupation" and "Hey hey. Ho ho. Corporate greed has got to go."

She said she had been coming to the Occupy Seattle demonstrations since early last week.

At the afternoon rally, Liam Wright, 24, who also has been participating in the demonstration since early last week, drew strong cheers when he urged the group to be skeptical of McGinn's overtures.

Wright, a Seattle Central Community College student, said the mayor and the Seattle Police Department "are hellbent on the destruction of this movement."

He said the movement needs people willing to stay at the park in defiance of the mayor and risk arrest. "We need to be unmanageable like they are in New York."

Other speakers urged students to stick with the "Occupy" movement, warning that the politically and economically powerful will not surrender their advantages voluntarily.

Faith Coben, 19, a student at Cornish College of the Arts, hand-lettered a sign reading, "Students deserve futures, not debt."

Coben has been part of the protest since last week. "I've seen more and more people struggling to make ends meet," she said, "and they're having trouble making it because the economy is so messed up."

She said students are "graduating with thousands of dollars of debt, and there are no jobs."

Earlier, on the UW campus, between 100 and 200 students and some professors gathered at Red Square at noon for an hourlong round of speeches, the first time the "Occupy" movement has touched the state's largest college campus.

They then marched through campus toward Westlake Park, briefly shutting down traffic on University Way, University Bridge and Eastlake Avenue. They were escorted by Seattle police.

Arendt Speser, a UW graduate student in English who teaches English composition there, said he was speaking out because he's concerned with the way state budget cuts have affected the school.

At one time, it was "almost a promise that you were guaranteed a seat here if you were from in-state and you worked hard," he said.

But increasingly, to pay the bills, the UW is accepting more out-of-state and international students, who pay higher tuition rates, he said.

"I've seen with my own eyes how directly this university has been impacted," said Speser, who said his salary for teaching undergraduate classes has been frozen for four years and he's recently started taking out student loans.

He said he wants to see the Legislature reassess the tax structure and close corporate loopholes.

Mark Engle, a student in the UW Foster School of Business, said he joined the protest because he believes money has distorted politics, and that the system needs to be changed.

Engle said he was in Berlin earlier this year when demonstrators helped persuade German Chancellor Angela Merkel to phase out nuclear power over the next 11 years.

The power of those protests convinced him that the Occupy Wall Street movement could be a change catalyst as well, he said.

"I love business, I love making money, but the problem is regulating it in a way that makes sense," Engle said.

"We're very much in solidarity: Get money out of politics," added Angela Herr, another Foster business school student.

NEW YORK — Responding to what he called unsanitary conditions at the private park serving as home base to the Occupy Wall Street protest for more than three weeks, Mayor Michael Bloomberg said Wednesday night that protesters would be made to leave temporarily as the property was cleaned in stages.

Bloomberg made the announcement after visiting Zuccotti Park in Lower Manhattan for the first time and telling protesters in person that the cleaning would begin Friday, a statement released by his office said.

He cited deteriorating sanitary conditions as the reason the park's owner, Brookfield Properties, wrote to the city conveying its concerns "about its inability to clean the park and maintain it in a condition fit for public use."

"The mayor is a strong believer in the First Amendment and believes that the protesters have a right to continue to protest," Caswell Holloway, the deputy mayor for operations, said in a statement.

"At the same time, the last three weeks have created unsanitary conditions and considerable wear and tear on the park. This situation is not in the best interests of the protesters, residents or the city."

The Bloomberg administration added that the park would be cleaned in stages, and that the protesters would be allowed to return to the areas that had been cleaned, "provided they abide by the rules that Brookfield has established for the park."

It was not immediately clear how many cleanup stages there would be, or how long the cleanup would take.

Bloomberg has said he believes the protesters have a right to congregate, and that they would not be removed by the police if they obeyed the laws.

But he has also been critical of their message and the disruption they have caused to Lower Manhattan.

He has suggested he does not believe the protesters will stick around when the weather turns cold.